Electron-discharge-tube structure



May 1, 1928.

L. SUTHERLIN ET AL ELECTRON DISCHARGE TUBE STRUCTURE Filed May 28, 1924 INVENTORS m 2 m aw LHn m WITNESSES:

' TTORNEY Patented May 1, 1928.

UNITED STATES PATENT OFFICE.

LEE surrmnnm AND mnmnT M. FREEMAN, or EAST PITTSBURGH, rnnnsynvmm, ASSIGNORS To wnsrnvenousr. ELECTRIC a MANUFACTURING country, A con- PORATION OF PENNSYLVANIA.

Applicationfiled ma 28', 1924. Serial No. 716,326.

Our invention relates to thermionic discharge devices and particularly to thermionlc triodes having a multi-strand fila- .mentary cathode.

An object of our device is to provide a convenient supporting means for a multistrand filamentary cathode.

' Another object of our invention is to provide a multi-strand cathode structure supvacuum tubes, it has been customary to seal into the press a sufficient number of wires to form the necessary number of supportlng hooks to carry the desired number of strands of the filament. This is objectionable because of the reduction in creepage distance across the press surface and because of the difficulty and complexity involved in sealing the large number of wires through the press.

Our invention provides means whereby the filament structure is carried on a single wire sealed in the press. c

ther objects and structural details of our invention Will be apparent from the following description when read in connection with the accompanying drawing wherein:

Fig. 1 is a view, partially in elevation and partially in section, of a structure embodying our invention,

Fig. 2 is a similar view of a modification, and

Fig. 3 is a horizontal sectional View taken on the line III-III of Fig. 2.

Referring to the figures, 1 is an evacuated container having a reentrant portion 2 and a press 3 thereon. The reentrant portion 2 is surrounded by a band 4 to which is attached upright wires 5 and 6 carrying an anode 7. An electrical connection is made to the anode structure 7 through the upright wire 6 b a lead wire 8 sealed through the press 3.. Z grid electrode 9 is supported by wires 11 and 12 that are also sealed through and into the press 3. Cathode lead wlres 14 and 15 are also sealed through the press 3. To these lead wires is attached a filament 16 which is threaded and supported by a structure comprisin a main supportin upright 17 that is scale in the press 3 and a lurality of supportinghooks.

eferring particularly to Fig. 1, the wire 17 has fused thereon, a glass bead 18 into which are fused supporting wires 19 and 21. The wire 17 also has attached thereto an additional hook 22. The filament 16 is attached at one end to the lead wire 14 and is threaded over the hook 19, under book 22, over hook 21 and attached at its other end to the lead wire 15.

Referring particularly to Fig. 2,the wire 17 has fused thereon, two glass beads 23 and 24. The head 23 has fused therein, hooks 25 and 26 and the head 24 has fused therein, the books 27 and 28. The to of wire 17 is further formed into the ad itional hook 29. The filament 16 is attached at one end to the lead wire 14 and threaded over the hook 27, threaded under the hook 23, threaded over the book 29, threaded under the hook 26, threaded over the hook 28 and further attached to lead wire 15.

B5; the construction above outlined, we are enabled to position a multi-strand filament properly with respect to a grid and anode electrode, whereby an electron emission from such a filamentary cathode may be adequately utilized and whereby the entire filament structure is'supported from a single wire sealed into the press.

By means of the structure described above, we are enabled to obtain the objects previously mentioned.

While we have shown only two embodiments of our invention, it is capable of various changes and modifications without departing from the spirit thereof and it is desired, therefore, that only such limitations shall be imposed thereon as are indicated in the priorart or in the appended claims.

We claim as our invention:

1. A thermionic discharge device comprising in combination an evacuated container having a reentrant portion and a press thereon, and anode,

grid and cathode elecr trodes therein, said cathode comprising a pair of lead wires sealed through said press, a main supporting wire sealed in said press, a glass bead thereon, auxlliary supgortin wires positioned and supported there y, an a filamentary cathode wire carried thereon and attached to said lead wires.

2. In a vacuum tube, a press, an oval I anode supported therefrom, a metal standard supported in said press and extending outsi e of said oval anode, a cathode com rising a plurality of successive lengths within I LEE SUTHERLIN. HUBERT M. FREEMAN. 

